1. Field of the Invention
The present invention relates to an information recording and reproducing apparatus for recording and/or reproducing information by irradiating a disk with laser light. In particular, the present invention is preferably used in an optical disk apparatus for recording/reproducing information with respect to a laminated disk such as a digital versatile disk (DVD).
2. Description of the Related Art
A conventional optical disk apparatus is provided with focus control means and tracking control means as means for allowing laser light to follow a track. In addition, an optical disk apparatus for recording/reproducing information with respect to a high-density disk such as a DVD drive is provided with so-called tilt control means for controlling an optical axis of laser light to be vertical to a disk surface.
Regarding such tilt control, for example, JP 2001-23213 A describes an optical disk apparatus for controlling a tilt using a focus control signal. More specifically, by inputting a focus control signal at a current recording/reproducing position in a tilt control circuit, and controlling a tilt correction mechanism based on the focus control signal, the influence of a tilt is cancelled in synchronization with a tilt amount due to disk rotation. This enables stable recording/reproduction to be performed with respect to an optical disk having surface wobbling.
The tilt control means shown in JP 2001-23213 A is preferably used in the case where the state of surface wobbling varies dynamically owing to the change in temperature in a drive and the like. However, in a laminated disk such as a DVD, the state of surface wobbling does not vary so much even when the temperature in a drive changes. Thus, the dynamic tilt control as in JP2001-23213 A is not necessarily required.
Furthermore, in the case of seeking a recording/reproducing position during recording/reproduction, when a tilt is detected from, for example, the state of a reflected beam one by one, a period of time from the end of a seek to the start of recording/reproduction becomes long. In the field of an optical disk apparatus, there is a demand for an increase in speed of a recording/reproducing operation. In this respect, a further increase in speed is required even in tilt control during a seek operation.